1. Field of the Invention
This invention most generally relates to use of grippers on high speed and high volume production equipment to hold and handle parts during manufacture and assembly. Grippers are generally mechanical devices, each with two or more fingers actuated by air (pneumatic), electric (solenoid), or oil (hydraulic) to open or close on the subject part.
Individual grippers used on high speed production equipment are generally designed to have a specific stroke length and motion, with a fixed open and closed dimension. They are often of two dominant types: those having fingers which remain "parallel" as they are moved to open or close, and those having fingers that rotate open and closed about a "fulcrum" at the base of the gripper.
Production equipment is often configured to accept interchangeable gripper chucks, each with different size grippers to accommodate required changes in production. The production changes usually necessitate the removal and replacement of individual gripper chucks to accommodate the change in the sizes of the material being handled in the production equipment, and also necessitate the owning of and maintenance of an inventory of gripper chucks with varying sizes of grippers to satisfy the range of production requirements.
2. Description of the Prior Art
Prior art in the related fields of this invention discloses the "fulcrum" and "parallel" types of grippers in a wide range of gripper sizes and chuck configurations, the use of turret mechanisms to mount more grippers on a given machine, means of mounting gripper chucks on robot arms, techniques for improving the sensitivity and effectiveness of the grip, and the utility of standard size, interchangeable chucks to provide a common mounting scheme for different size grippers. The art discloses that incremental improvements have been valuable to the industry.
It is obvious that there are overhead costs and other problems associated with the necessity of owning and maintaining a large inventory of gripper chucks and having them readily available to the production floor. There are also inherent problems associated with the need to interchange chucks on production equipment as pilot or production requirements change, examples of which are reduced levels of productivity and increased production costs. These problems remain largely unsolved.
There are patents which disclose ways of obtaining versatility using a multiple gripper turret as in Spacher et al, U.S. Pat. No. 4,930,976, exchangeable gripping jaws as in Weisner et al, U.S. Pat. No. 4,715,636, a dual axis gripper as in Barrows, U.S. Pat. No. 4,626,013, a complicated scheme for use in an automated foundry plant as in Jacobsen, U.S. Pat. No. 4,840,416 and a gripper having a plurality of pseudo spherical contact pads permitting a plurality of points of contact with an object to be gripped as in Guinot et al, U.S. Pat. No. 4,653,793. Wright, U.S. Pat. No. 4,610,597 teaches a mechanical interface for joining a gripper to a robot wrist.
The following U.S. patents are representative of the state of the art in the field of this invention.
Wiesner et al U.S. Pat. No. 4,715,636, discloses the utility of exchangeable gripper jaws for customizing grippers for the user's specific needs; a useful technique but it leads one to greater inventory problems, not less.
Spacher et al U.S. Pat. No. 4,930,976, teaches the use of a multigripper turret to enhance the capability of a parts-handling station; a useful technique but not a cost-effective solution for simpler operations nor a reduction to gripper inventory requirements.
it is important to note that none of the prior art known to the inventor hereof discloses or suggests the invention disclosed herein.